Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 251915

Area Forecast Discussion
National Weather Service Gaylord MI
315 PM EDT Tue Oct 25 2016

.SHORT TERM...(This evening and overnight)
Issued at 313 PM EDT Tue Oct 25 2016

Strong surface ridge axis remains over Michigan this afternoon. A
few light lake effect rain showers continue to hold on across some
locations in NW Lower Michigan despite strengthening subsidence...
dry air and lowering inversion heights. Over-lake instability seems
to still be winning out over an increasingly more hostile synoptic
environment...but this is and will continue to give way to high
pressure as well as loss of diurnal heating/instability as we head
toward evening. Most locations warmed into the 40s today...even a
few lower 50s along the Lake Michigan shoreline. Clearing skies
tonight will lend to a descent diurnal temp drop...with most
locations falling into the upper 20s and lower 30s tonight.

Attention now turns to the developing storm system to the lee of the
Rockies. Mid/high clouds will begin to increase from SW to NE late
tonight in advance of this system. Light/calm winds during the
evening hours will increase just a bit overnight as well in response
to some tightening of the low level pressure gradient. Expect temps
will begin to slowly warm before sunrise as a result. Still expect
temps should warm to above freezing before deep moisture arrives and
any precip develops. No doubt...widespread precip will develop on
Wednesday from SW to NE across our entire CWA as deep moisture
surges northward ahead of the low. Again...expect precip should be
all liquid on least until very late afternoon/early
evening when some colder air begins to wrap around the northern
periphery of the surface low tracking south of our CWA. Diurnal
heating will also begin to wane by this time. NAM BUFR soundings
still show precip becoming mixed with snow by around 22Z or so. High
temps Wednesday afternoon will only warm into the low to mid 40s
thanks to thick cloud cover...precip and some low level CAA
beginning late in the day.

.LONG TERM...(Wednesday through Tuesday)
Issued at 313 PM EDT Tue Oct 25 2016

Wednesday night through Friday

High impact weather...Snow Wednesday night in higher elevations.

Jet currently punching into the PAC NW helps spin up fairly vigorous
surface low that reaches MI Wednesday. Low track takes it across IA
and then along the MI/IN border Wednesday night and then into Lake
ON Thursday. 40-50kt 850mb jet just ahead of the low will advect
moisture/warm air north over boundary in southern part of the state.

Low tracks south of the area but strong warm advection/isentropic
lift early Thursday morning with 40-50kt 850mb jet moving in ahead
of the surface low. We are far enough north to be in the colder air
for a mix or change to snow in higher elevations Wednesday night.
Warm advection strong enough to change everyone back over to rain
maybe as early as before daybreak Thursday.

Deeper moisture to the south so QPF will be on the light side but
isentropic lift quite strong. PWAT values generally 0.5 north to
0.75 south. Storm total QPF values should range from around 0.10
north to 0.60 south between 18z Wednesday and 00z Friday.

Temperature profile shows cold enough air for snow just above the
ground. 850mb temps in the 0 to -4C range Wednesday night. Problem
is depth of above freezing air near the surface. Right now it looks
like the chance of precipitation mixing with or changing to snow
will have to be in the higher elevations inland and the UP overnight
Wednesday night. Strong lift in advance of the 850mb jet will help
the changeover to snow between midnight and daybreak with maybe some
bursts of low visibility large-flake snowfall.


Pattern looks to remain active through the extended period. Rain
chances will carry through the weekend as a pair of occluding, weak
lows move through the region. A more robust system will be in the
area early next week, but confidence is quite low as to where it
will pass. The current storm track varies from well north of us to
tracking through the U.P., with the more southern track bringing
some decent rainfall. Temperatures will be above normal through the
period, and any precipitation will be of the liquid variety.



.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 100 PM EDT Tue Oct 25 2016

Lingering light lake effect rain showers will continue to impact
mainly the TVC area during the rest of the afternoon before ending
this evening as the ridge axis rides overhead. Clouds will
increase...lower and thicken overnight ahead of a complex area of
low pressure currently developing to the lee of the Rockies. This
low will push into Illinois and Southern Wisconsin by Wednesday
afternoon. Precip will develop from SW to NE beginning early
Wednesday and will continue to impact our region Wednesday night
into Thursday. Precip will begin as rain on Wednesday...but will
begin to mix with and possibly change to snow Wednesday night.
Thru 18Z Wednesday...conditions will remain VFR thru the period
despite increasing/lowering/thickening clouds ahead of the low.
North winds less AOB 10 kts this afternoon will become
light/variable this evening...and will then shift to the east on
Wednesday ahead of the low.


Issued at 313 PM EDT Tue Oct 25 2016

Winds and waves will remain below SCA criteria thru tonight and into
early Wednesday as the surface ridge axis overhead slowly begins to
give way to an approaching low pressure system. Low level pressure
gradient will begin to tighten by mid Wednesday morning...which will
likely boost winds and waves into SCA criteria across most of Lake
Michigan for the rest of Wednesday and likely into Wednesday night
as well. Widespread rain showers will develop from SW to NE across
Northern Michigan on Wednesday as deep moisture surges northward
ahead of this system. Precip will become mixed with snow across
Eastern Upper Michigan and within the higher elevations of Northern
Lower Michigan by Wednesday night.


LM...SMALL CRAFT ADVISORY from 11 AM to 8 PM EDT Wednesday for LMZ323-



LONG TERM...Farina/Mayhew
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